Adding new tab to transaction IW31/IW32/IW33

Hi all,

This migh be easy to some of you. I would just like to ask for your help on how can I add a new tab to transactions IW31/IW32/IW33. I found a BADI for this -> IWO_UI_USEFLEX. But dunno how to start in creating a new tab for the screen of the said transactions. Any help is very much appreciated. Thanks.